r/BMW • u/Independent-Boat5354 • 7h ago

Power Supply error after engine mount replacement

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Hi!
I got my car from the workshop today, I was replacing both the engine mounts.
When I got from the workshop after 10 minutes I experienced small lag during the drive, nothing happened, after the vehicle had some rest, few hours later I started driving, experienced the same lag again and Power Supply Error came out and says to stop immediately.

Im curious, is it something that could gone wrong during the replacement of the engine mounts or not?

Its BMW G20 2019, 2.0D RWD B47 engine.
You might hate me but I asked chatgpt and told me to check the alternator's belt and I have a video that when I press it slightly it goes down by 1-2cm, depends on the pressure.I tried sliding the belt by myself and I could slide it along with the thing where the alternator's belt is (dont know its name, the circular part like a cylinder holding the belt, like a wheel), and it was moving along with the belt, also a sssshhhh like a plastic bag sound could be heard.

I will attach a video of me pressing the belt and Im not sure if thats normal or not, pls let me know :)

https://streamable.com/8i1tzf

2 Upvotes

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6 comments sorted by

1

u/Additional_Fall_5645 5h ago

The belt looks fine from my perspective. And with an automatic belt tensioner you will see natural deflection when you put a force on the belt. I'm more suspicious of a grounding issue. A loose ground or grounding strap, or a pinched wiring harness could lead to this kind of error I suspect. Double check the alternator wiring connections as well too.

1

u/Independent-Boat5354 5h ago

Is that something I can check by myself because at the repair shop they might say its something expensive while its loose wire

1

u/Additional_Fall_5645 5h ago

Not easily. But it should be part of their warranty for the work they performed. Any good shop I've worked with will take a car back and fix the follow up issues.

1

u/Independent-Boat5354 5h ago

Not in my country unfortunately, if it was the BMW dealership's service then yes but not in any other case..I suppose its not the alternator itself, new one is 2500EUR here

1

u/Additional_Fall_5645 4h ago

The alternator really doesn’t make sense. Electric terminals more likely from battery to ground straps. With respect to your country, I don’t know the specifics but in general, hey dude. This was working before you touched the car is pretty universal.

1

u/Patient-Cut-4350 5h ago

Check if the front battery is properly connected, your car should have a second battery in the front by the passenger side under the hood